Drugs may be delivered to patients by a variety of methods including oral, intravenous, intramuscular, inhalation, topical, subcutaneous delivery or delivery directly or locally to the treatment site (e.g., intrathecally, intraspinally, intraarticularly, etc.). The method of delivery chosen depends, among other things, upon the condition being treated, desired therapeutic concentration of the drug to be achieved in the patient and the duration of drug concentration that must be maintained.
Recently, drug depots have been developed which allow a drug to be introduced or administered to sites beneath the skin of a patient so that the drug is slowly released over a long period of time. Such drug depots allow the drug to be released from the depot in a relatively uniform dose over weeks, months or even years. This method of administering drugs is becoming especially important and popular in modulating the immune, inflammation and/or pain responses in treatment of chronic conditions including rheumatoid arthritis, osteoarthritis, sciatica, carpal tunnel syndrome, lower back pain, lower extremity pain, upper extremity pain, cancer, tissue pain and pain associated with injury or repair of cervical, thoracic, and/or lumbar vertebrae or intervertebral discs, rotator cuff, articular joint, TMJ, tendons, ligaments, muscles, and the like.
Sometimes, after the drug depot is implanted at the treatment site, the drug depot may migrate from the implant site as physiological conditions change (e.g., repair and regeneration of cells, tissue ingrowth, movement at implant site, etc.). At times, this may reduce efficacy of the drug as the drug depot migrates away from the implant site and lodges in a distant site. If this occurs, the drug depot will have to be removed from the distant site and have to be reinserted causing additional physical and psychological trauma to a patient. In some cases, if the drug depot migrates into a joint, the drug depot may inhibit movement. In more severe cases, if the drug depot migrates, it may restrict blood flow causing an ischemic event (e.g., embolism, necrosis, infarction, etc.), which could be detrimental to the patient.
Previously, implantable devices have been used to stabilize tissue (e.g., bone, joints, etc.) or used to bridge gaps between ruptured tissues. These implantable devices include rigid anchoring members, which allow little or no movement at the implant site; flexible anchoring members that stabilize the joint and allow some degree of movement; retaining anchoring members that are bolted to one side of a joint and engage like a hook on the opposite side; and anchoring members with articular connections to bridge gaps and stabilize tissue.
New implantable devices are needed that improve the drug depot efficacy and reduce the risk associated with unwanted migration of the drug depot. Implantable devices that allow accurate and precise implantation of the drug depot with minimal physical and psychological trauma to the patient are also needed.